In recent years, flexible display devices have become more and more common in the display market, and attract consumers' attention. Development and application of the flexible display subverted a concept that display can only be fixed to one flat panel in the past, and the flexible display has demonstrated various market application prospects due to advantages, such as thinness, flexibility, deformation and customizability, and have emerged in fields, such as wearable devices, transparent displays, household electrical appliances and smart phones.
Technologies to realize the flexible display can be classified into two aspects: a front-panel technology and a back-panel technology. The front-panel technology of the flexible display has a certain compatibility with the front-panel technology of the flat panel display, and the mass production degree is high; however, the back-panel technology of the flexible display is difficult to be compatible with a module technology of the original flat panel display technology after the glass substrate is taken down, and it is difficult to develop it on a flexible substrate.